The SBIG FW5-8300 5-Position Filter Wheel with Baader 36 mm LRGB Filters Holds five 36 mm drop in filters for un-vignetted imaging at any f/ratio with the ST-8300 or ST-4000XM cameras. It is now through the prototype stage. There have been two modifications to the original design that have required separate prototyping. It is a single carousel design with a new filter retaining system that makes changing filters easier than with individual retaining screws for each filter. The carousel is also interchangeable for swapping out 5 filter sets all at the same time. The telescope side of the filter wheel has a round adapter plate with standard t-threads. This piece can easily be removed and replaced with an optional Nikon lens adapter.
The Baader Blue filter passes virtually all of the H-Beta and O-III lines, while the Green filter is able to capture all of the O-III line, without encroaching into the H-Beta line. None of the light is wasted by either filter. In this way, O-III is represented as it should be, a teal (blue-green) color and H-Beta is captured solely in the blue. Never before has this degree of separation been achieved and with such high transmission of both lines. In addition, the Green and Red filter passbands nearly touch, leaving only a sharp notch to block out the primary Mercury/Sodium light pollution line at 580 nm. The high transmission everywhere else delivers the shortest combined exposures possible with every detector.
